To run the Spore Creature Creator Demoo in Tiger, just edit the Info.plist file you'll find inside the demo application. Control-click on Spore Creature Creator.app, choose Show Package Contents from the pop-up menu, and open the Contents folder.

With Info.plist open in your favorite text editor, locate these strings:

<key>MinimumSystemVersion</key>
<string>10.5.3</string>

Edit the strings as follows:

<key>MinimumSystemVersion</key>
<string>10.4.11</string>

Save the changes and quit the editor. The demo works great on a first generation 3GHz Mac Pro with an ATI X1900XT video card.

[robg adds: System requirements are typically based on features in a given level of the OS, so there may be unknown issues if you use this hint to run the demo on an earlier version of the OS.]
May be this will work for the full version too...

Hint fails for me on 10.4.11, MBP. That key didn't exist in my Info.plist file, and adding it changed nothing. The installer still starts and immediately puts up an error dialog complaining about the integrity of my hard drive. How rude; the installer barely knows my hard drive!

Looking inside the installer DMG, not the "demo application" as noted, the only place I see a variable that meets that description is in the /Contents/Resources location and it's called tginstall.plist.

However, I cannot save the updated plist, no matter how I set permissions. Yes, I'm logged in as a administrator.

And the stars/planets are swirling around but if I try to click on anything it takes me out of the program and into Firefox, where it loads the EA Store/Customer Support website. Is there anything more I can do? I'm trying to run it on a relatively new Macbook.